Fibre reactive formazan dyes which can be used for the dyeing and printing of hydroxyl-group-containing or nitrogen-containing fibre materials, such as cotton or wool, are known and described, for example, in U.S. Pat. Nos. 4,024,123, 4,370,145, 4,556,706, 4,720,542, 4,754,023, 4,906,736, 4,935,500, and WO2007085574.
Nowadays reactive dyes are required that have sufficient substantivity and at the same time have good ease of washing off of unfixed dye. They should also have a good tinctorial yield and high reactivity, the objective being to provide especially dyeings and prints having high degrees of fixing. The dyes should also yield dyeings and prints having good all-round fastness properties, for example light-fastness and wet-fastness properties. The fibre reactive formazan dyes hitherto known do not satisfy all these requirements. In particular, dyeings prepared with the known dyestuffs have insufficient wash- and chlorine fastness.
The problem underlying the present invention is accordingly to find, for the dyeing or printing of fibre materials, novel improved blue dyeing fibre reactive dyes having the qualities characterised above to a high degree.